An inverted cone-shaped cold screen and refrigerated infrared detector

Abstract

The invention relates to the technical field of infrared detectors, and in particular to an inverted cone-shaped cold shield, which comprises: a cold shield side wall and a filter mounting plate located at the upper end of the cold shield side wall; wherein a cold shield light-through hole is provided at the center of the filter mounting plate, and an annular filter bonding area is provided around the cold shield light-through hole; the cold shield side wall comprises a first cold shield side wall located at the lower part and a second cold shield side wall located at the upper part, the first cold shield side wall and the second cold shield side wall are connected to each other, the second cold shield side wall is an inverted conical surface, the upper end diameter of the second cold shield side wall is larger than the lower end diameter thereof, and the lower end diameter of the second cold shield side wall matches the upper end diameter of the first cold shield side wall; the cold shield of the invention has an overall structure of being larger at the top and smaller at the bottom, which enlarges the inner diameter of the cold shield side wall while ensuring the bonding strength of the filter, thereby playing a role in suppressing stray light.

Description

Technical Field

[0001] The invention relates to the technical field of infrared detectors, and in particular to an inverted cone cold screen and a refrigerated infrared detector having the inverted cone cold screen. Background Art

[0002] Stray light refers to other non-imaging light that diffuses on the detector surface in addition to the imaging light in the optical system, as well as imaging light that reaches the detector through abnormal optical paths. The performance of cooled infrared detectors is easily affected by various stray lights in the test or working environment. Stray light will affect the signal-to-noise ratio and image contrast of the target detected by the detector, thereby reducing the image clarity and even forming scattered light spots. In severe cases, the target signal will be completely annihilated in the stray light background radiation, making the target unable to be identified and causing the detector to fail.

[0003] A cold shield structure is usually added to absorb stray light. However, the existing cold shield structure will cause some stray light to still be reflected to the chip after passing through the side wall, thus affecting the uniformity of the detector response. Summary of the invention

[0004] The purpose of the present invention is to provide an inverted cone-shaped cold shield and a refrigerated infrared detector having the inverted cone-shaped cold shield. The angle between the side wall of the cold shield and the substrate is β (β>90°), and the cold shield is generally large at the top and small at the bottom. While ensuring the bonding strength of the filter, the inner diameter of the side wall of the cold shield is enlarged, thereby suppressing stray light.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] An inverted cone-shaped cold shield, comprising: a cold shield side wall and a filter mounting plate located at the upper end of the cold shield side wall, wherein the upper surface of the filter mounting plate forms a filter mounting surface for mounting a filter; wherein:

[0007] A cold screen light-through hole is provided at the center of the filter mounting plate, and an annular filter bonding area is provided around the cold screen light-through hole;

[0008] The cold shield side wall comprises a first cold shield side wall located at the bottom and a second cold shield side wall located at the top, the first cold shield side wall and the second cold shield side wall are connected to each other, the second cold shield side wall is an inverted conical surface, the upper end diameter of the second cold shield side wall is larger than the lower end diameter thereof, and the lower end diameter of the second cold shield side wall matches the upper end diameter of the first cold shield side wall; wherein,

[0009] The width s of the filter bonding area is:

[0010] s=d+d 0

[0011] Wherein, d is the distance between point M' and point N, point N is located at the outer edge of the filter mounting plate, and point M' and point N are located on the same diameter of the filter mounting plate; point M' is the projection of point A on the filter mounting plate; point A is the point at the lower end of the second cold shield side wall;

[0012] Among them, d 0 is the distance between point M' and the inner end point O of the cold shield aperture, and point M', point N and the inner end point O are located on the same diameter of the filter mounting plate;

[0013] The distance d between point M' and point N satisfies:

[0014] d=(Hh)cot(180°-β)

[0015] Wherein, H is the height of the cold shield side wall; h is the height of the first cold shield side wall; β is the angle between the second cold shield side wall and the focal plane;

[0016] The width s of the filter bonding area satisfies:

[0017]

[0018] Wherein, D is the diameter of the filter mounting plate, and L is the diameter of the cold screen light hole.

[0019] In the above-mentioned inverted cone cold shield, the diameter of the filter mounting plate satisfies:

[0020]

[0021] Where Q is the inner diameter of the window frame.

[0022] In the above-mentioned inverted cone-shaped cold shield, the side wall of the first cold shield is a cylindrical surface, and the first cold shield side wall has a constant diameter.

[0023] The above-mentioned inverted cone-shaped cold shield, wherein the inverted cone-shaped cold shield is made of nickel-cobalt alloy, the outer wall of the inverted cone-shaped cold shield is provided with a bright gold-plated layer, and the inner wall of the inverted cone-shaped cold shield is provided with a blackened layer.

[0024] In the above-mentioned inverted cone-shaped cold shield, one or more light-blocking rings are provided inside the cold shield side wall, and the light-blocking rings are located inside the second cold shield side wall.

[0025] In the above-mentioned inverted cone-shaped cold shield, a light-blocking ring light-through hole is provided at the center of the light-blocking ring, and the light-blocking ring light-through hole is rectangular, circular and / or rounded rectangular.

[0026] The above-mentioned inverted cone cold shield, wherein an annular groove is provided on the upper filter bonding area of ​​the filter mounting plate, and the annular groove is arranged around the cold shield light through hole. An exhaust hole is also provided on the filter mounting plate, and the exhaust hole connects the annular groove and the side of the filter mounting plate.

[0027] In the above-mentioned inverted cone-shaped cold shield, a cold shield mounting plate is further provided at the lower end of the first cold shield side wall, and a centering line is provided on the cold shield mounting plate and / or the filter mounting plate.

[0028] An inverted cone-shaped cold shield, comprising: a cold shield side wall and a filter mounting plate located at the upper end of the cold shield side wall; wherein:

[0029] A cold screen light-through hole is provided at the center of the filter mounting plate, and an annular filter bonding area is provided around the cold screen light-through hole;

[0030] The cold shield side wall is an inverted conical surface, and the upper end diameter of the cold shield side wall is larger than the lower end diameter; wherein,

[0031] The width s of the filter bonding area is:

[0032] s=d+d 0

[0033] Wherein, d is the distance between point M' and point N, point N is located at the outer edge of the filter mounting plate, and point M' and point N are located on the same diameter of the filter mounting plate; point M' is the projection of point A on the filter mounting plate; point A is the point at the lower end of the cold shield side wall;

[0034] Among them, d 0 is the distance between point M' and the inner end point O of the cold shield aperture, and point M', point N and the inner end point O are located on the same diameter of the filter mounting plate;

[0035] The distance d between point M' and point N satisfies:

[0036] d=H cot(180°-β)

[0037] Wherein, H is the height of the cold shield side wall; β is the angle between the cold shield side wall and the focal plane;

[0038] The width s of the filter bonding area satisfies:

[0039]

[0040] Wherein, D is the diameter of the filter mounting plate, and L is the diameter of the cold screen light hole.

[0041] A cooled infrared detector, comprising any one of the inverted cone cold shields described above.

[0042] The present invention has the following positive effects compared with the prior art due to the adoption of the above technology:

[0043] (1) The cold shield of the present invention has a structure that is larger at the top and smaller at the bottom. While ensuring the bonding strength of the filter, the inner diameter of the cold shield side wall is enlarged to suppress stray light. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a three-dimensional schematic diagram of an inverted cone-shaped cold shield in an embodiment of the present invention;

[0045] Figure 2 is a cross-sectional schematic diagram of an inverted cone-shaped cold shield in an embodiment of the present invention;

[0046] In the attached drawings: 1. cold screen side wall; 11. first cold screen side wall; 12. second cold screen side wall; 2. filter mounting plate; 21. cold screen light hole; 22. filter bonding area; 23. annular groove; 24. exhaust hole; 3. light blocking ring; 4. cold screen mounting plate; 5. centering line. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] In the description of the present invention, it is necessary to understand that the orientation or position relationship indicated by the terms such as "upper", "lower", "left", "right", "inside", "outside", "front", "back", "lateral" and "vertical" is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or original referred to must have a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0049] First embodiment:

[0050] See also Figure 1 to Figure 2As shown, a preferred embodiment of an inverted cone cold shield is shown, comprising: a cold shield side wall 1 and a filter mounting plate 2 located at the upper end of the cold shield side wall 1; wherein a cold shield light hole 21 is provided at the center of the filter mounting plate 2, and an annular filter bonding area 22 is provided around the cold shield light hole 21; the cold shield side wall 1 comprises a first cold shield side wall 11 located at the lower part and a second cold shield side wall 12 located at the upper part, the first cold shield side wall 11 and the second cold shield side wall 12 are connected to each other, the second cold shield side wall 12 is an inverted conical surface, the upper end diameter of the second cold shield side wall 12 is larger than the lower end diameter thereof, and the lower end diameter of the second cold shield side wall 12 matches the upper end diameter of the first cold shield side wall 11. Preferably, the cold shield side wall 1 is an integrated structure, that is, the first cold shield side wall 11 and the second cold shield side wall 12 are connected in an integrated manner, and the upper end of the first cold shield side wall 11 is the lower end of the second cold shield side wall 12.

[0051] Wherein, the width s of the filter bonding area 22 is:

[0052] s=d+d 0

[0053] Wherein, d is the distance between point M' and point N, point N is located at the outer edge of the filter mounting plate 2, and point M' and point N are located on the same diameter of the filter mounting plate 2; point M' is the projection of point A on the filter mounting plate 2; point A is the point at the lower end of the second cold shield side wall 12;

[0054] Among them, d 0 is the distance between point M' and the inner end point O of the cold shield light aperture 21, and point M', point N and the inner end point O are located on the same diameter of the filter mounting plate 2;

[0055] The distance d between point M' and point N satisfies:

[0056] d=(Hh)cot(180°-β)

[0057] Wherein, H is the height of the cold shield side wall 1; h is the height of the first cold shield side wall 11; β is the angle between the second cold shield side wall 12 and the focal plane;

[0058] Specifically, see Figure 2 As shown, β is the inner angle between the second cold shield side wall 12 and the focal plane. Since the second cold shield side wall 12 is an inverted conical surface with a larger top and a smaller bottom, as shown in FIG. Figure 2 The angle β is shown as an obtuse angle.

[0059] The width s of the filter bonding area 22 satisfies:

[0060]

[0061] Wherein, D is the diameter of the filter mounting plate 2 , and L is the diameter of the cold shield light aperture 21 .

[0062] The included angle β between the second cold shield side wall 12 and the focal plane is adjusted so that the width s of the filter bonding area 22 meets the requirements of the above formula.

[0063] Further, as a preferred embodiment, the diameter of the filter mounting plate 2 satisfies:

[0064]

[0065] Where Q is the inner diameter of the window frame of the cooled infrared detector.

[0066] Furthermore, as a preferred embodiment, the first cold shield side wall 11 is a cylindrical surface, and the first cold shield side wall 11 has a constant diameter.

[0067] In some other embodiments, the first cold shield side wall 11 is inclined or curved. In this case, h is the height of the first cold shield side wall 11, specifically refers to the distance from the upper end of the first cold shield side wall 11 to the focal plane, especially the vertical distance from the upper end of the first cold shield side wall 11 to the focal plane.

[0068] Furthermore, as a preferred embodiment, the inverted cone-shaped cold shield is made of nickel-cobalt alloy, the outer wall of the inverted cone-shaped cold shield is provided with a bright gold-plated layer, and the inner wall of the inverted cone-shaped cold shield is provided with a blackened layer.

[0069] Further, as a preferred embodiment, the thickness of the bright gold-plated layer is 0.1-5 μm, and the thickness of the blackened layer is 5-60 μm.

[0070] Furthermore, as a preferred embodiment, a blackening layer is formed by a blackening treatment, and materials such as SiC and graphite may be used for the blackening treatment.

[0071] Furthermore, as a preferred embodiment, blackening processes such as electroplating blackening, chemical blackening, and coating can be used.

[0072] Further, as a preferred embodiment, one or more light blocking rings 3 are provided inside the cold shield side wall 1 , and the light blocking rings 3 are located inside the second cold shield side wall 12 .

[0073] Further, as a preferred embodiment, a light-blocking ring light-through hole is provided at the center of the light-blocking ring 3, and the light-blocking ring light-through hole is rectangular, circular and / or rounded rectangular.

[0074] Furthermore, as a preferred embodiment, an annular groove 23 is provided on the upper filter bonding area 22 of the filter mounting plate 2, and the annular groove 23 is arranged around the cold screen light hole 21. An exhaust hole 24 is also provided on the filter mounting plate 2, and the exhaust hole 24 connects the annular groove 23 and the side of the filter mounting plate 2.

[0075] Further, as a preferred embodiment, the width of the exhaust hole 24 is 0.5-2 mm, and the depth of the exhaust hole 24 is 0.2-1 mm.

[0076] Further, as a preferred embodiment, a cold shield mounting plate 4 is further provided at the lower end of the first cold shield side wall 11 , and a centering line 5 is provided on the cold shield mounting plate 4 and / or the filter mounting plate 2 .

[0077] Further, as a preferred embodiment, a ceramic substrate is provided, a cold shield mounting plate 4 of the inverted cone cold shield is mounted on the upper surface of the ceramic substrate, and the chip is mounted on the upper surface of the ceramic substrate. In this case, the upper surface of the ceramic substrate is the focal plane. Preferably, the cold shield mounting plate 4 is bonded to the ceramic substrate.

[0078] Further, as a preferred embodiment, the centering line 5 is a groove structure.

[0079] Further, as a preferred embodiment, the depth of the centering line 5 is 0.05 mm.

[0080] Further, as a preferred embodiment, the centering lines 5 are arranged in a cross shape.

[0081] Furthermore, as a preferred embodiment, a cooled infrared detector is provided, which includes an inverted cone-shaped cold shield.

[0082] Second embodiment:

[0083] The present invention also provides another preferred embodiment of an inverted cone-shaped cold shield, comprising: a cold shield side wall and a filter mounting plate located at the upper end of the cold shield side wall; wherein a cold shield light-through hole is opened at the center of the filter mounting plate, and an annular filter bonding area is arranged around the cold shield light-through hole; the cold shield side wall is an inverted conical surface, and the upper end diameter of the cold shield side wall is larger than the lower end diameter thereof

[0084] Among them, the width s of the filter bonding area is:

[0085] s=d+d 0

[0086] Wherein, d is the distance between point M' and point N, point N is located at the outer edge of the filter mounting plate, and point M' and point N are located on the same diameter of the filter mounting plate; point M' is the projection of point A on the filter mounting plate; point A is the point at the lower end of the cold screen side wall;

[0087] Among them, d 0 is the distance between point M' and the inner end point O of the cold screen aperture, and point M', point N and the inner end point O are located on the same diameter of the filter mounting plate;

[0088] The distance d between point M' and point N satisfies:

[0089] d=H cot(180°-β)

[0090] Wherein, H is the height of the cold shield side wall; β is the angle between the cold shield side wall and the focal plane;

[0091] The width s of the filter bonding area satisfies:

[0092]

[0093] Where D is the diameter of the filter mounting plate and L is the diameter of the cold screen aperture.

[0094] Compared with the first embodiment, the cold shield side wall in the second embodiment is equivalent to the second cold shield side wall 12 in the first embodiment, and the second embodiment does not have the first cold shield side wall 11 in the first embodiment.

[0095] In other words, the second embodiment is actually the case where h=0 in the first embodiment.

[0096] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. An inverted cone-shaped cold shield, characterized in that: include: A cold shield side wall and a filter mounting plate located at the upper end of the cold shield side wall; wherein, A cold screen light-through hole is provided at the center of the filter mounting plate, and an annular filter bonding area is provided around the cold screen light-through hole; The cold shield side wall comprises a first cold shield side wall located at the bottom and a second cold shield side wall located at the top, the first cold shield side wall and the second cold shield side wall are connected to each other, the second cold shield side wall is an inverted conical surface, the upper end diameter of the second cold shield side wall is larger than the lower end diameter thereof, and the lower end diameter of the second cold shield side wall matches the upper end diameter of the first cold shield side wall; wherein, The width s of the filter bonding area is: s=d+d0 Wherein, d is the distance between point M' and point N, point N is located at the outer edge of the filter mounting plate, and point M' and point N are located on the same diameter of the filter mounting plate; point M' is the projection of point A on the filter mounting plate; point A is the point at the lower end of the second cold shield side wall; Wherein, d0 is the distance between point M' and the inner end point O of the cold shield aperture, and point M', point N and the inner end point O are located on the same diameter of the filter mounting plate; The distance d between point M' and point N satisfies: d=(Hh)cot(180°-β) Wherein, H is the height of the cold shield side wall; h is the height of the first cold shield side wall; β is the angle between the second cold shield side wall and the focal plane; The width s of the filter bonding area satisfies: Wherein, D is the diameter of the filter mounting plate, and L is the diameter of the cold screen light hole.

2. The inverted cone cold shield according to claim 1, characterized in that: The diameter of the filter mounting plate satisfies: Wherein, Q is the inner diameter of the window frame, and D is the diameter of the filter mounting plate.

3. The inverted cone cold shield according to claim 1, characterized in that: The first cold shield side wall is a cylindrical surface, and the first cold shield side wall has a constant diameter.

4. The inverted cone cold shield according to claim 1, characterized in that: The inverted cone-shaped cold shield is made of nickel-cobalt alloy, the outer wall of the inverted cone-shaped cold shield is provided with a bright gold-plated layer, and the inner wall of the inverted cone-shaped cold shield is provided with a blackened layer.

5. The inverted cone cold shield according to claim 1, characterized in that: One or more light blocking rings are arranged inside the cold shield side wall, and the light blocking rings are located inside the second cold shield side wall.

6. The inverted cone cold shield according to claim 5, characterized in that: A light-blocking ring light-through hole is provided at the center of the light-blocking ring, and the light-blocking ring light-through hole is rectangular, circular and / or rounded rectangular.

7. The inverted cone cold shield according to claim 1, characterized in that: A cold shield mounting plate is also provided at the lower end of the first cold shield side wall, and a centering line is provided on the cold shield mounting plate and / or the filter mounting plate.

8. An inverted cone-shaped cold shield, characterized in that: include: A cold shield side wall and a filter mounting plate located at the upper end of the cold shield side wall; wherein, A cold screen light-through hole is provided at the center of the filter mounting plate, and an annular filter bonding area is provided around the cold screen light-through hole; The cold shield side wall is an inverted conical surface, and the upper end diameter of the cold shield side wall is larger than the lower end diameter; wherein, The width s of the filter bonding area is: s=d+d0 Wherein, d is the distance between point M' and point N, point N is located at the outer edge of the filter mounting plate, and point M' and point N are located on the same diameter of the filter mounting plate; point M' is the projection of point A on the filter mounting plate; point A is the point at the lower end of the cold shield side wall; Wherein, d0 is the distance between point M' and the inner end point O of the cold shield aperture, and point M', point N and the inner end point O are located on the same diameter of the filter mounting plate; The distance d between point M' and point N satisfies: d=Hcot(180°-β) Wherein, H is the height of the cold shield side wall; β is the angle between the cold shield side wall and the focal plane; The width s of the filter bonding area satisfies: Wherein, D is the diameter of the filter mounting plate, and L is the diameter of the cold screen light hole.

9. A refrigerated infrared detector, characterized in that: The inverted cone cold shield comprises the inverted cone cold shield as described in any one of claims 1 to 8.

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